Howdy!
Hoping this is a reasonable/appropriate forum for this question.
I'm trying to get a new sander working in my shop. It runs on 480V 3ø. It's fed from two 230V phase converters coupled together (one 20HP the other 30HP), which then goes through a 45KVA, reverse-fed transformer to get to 480V for the tool. That part's all working.
The sander has two sanding heads. One's got a 30HP motor, the other has a 17HP motor. The smaller one works fine. The larger one notsomuch. When I hit the starter switch (DOL wired) the contactor stutters. I assume what's happening here is that the inrush current is dropping the voltage sufficiently that the coil in the contactor releases and the circuit opens, which then bumps the voltage back up allowing the contactor to close, ad nauseum until I release the button. (Which I do quite quickly.)
There's plenty of amperage to run the tool at sanding load as long as I don't push it really hard, but I need to figure a way to get that big motor spinning. I'd really like to avoid buying a soft start or something like that since it's both expensive and requires a bunch of rewiring. Is there a way to add some big capacitors or something to get past the inrush?
Thanks,
-Ben
Hoping this is a reasonable/appropriate forum for this question.
I'm trying to get a new sander working in my shop. It runs on 480V 3ø. It's fed from two 230V phase converters coupled together (one 20HP the other 30HP), which then goes through a 45KVA, reverse-fed transformer to get to 480V for the tool. That part's all working.
The sander has two sanding heads. One's got a 30HP motor, the other has a 17HP motor. The smaller one works fine. The larger one notsomuch. When I hit the starter switch (DOL wired) the contactor stutters. I assume what's happening here is that the inrush current is dropping the voltage sufficiently that the coil in the contactor releases and the circuit opens, which then bumps the voltage back up allowing the contactor to close, ad nauseum until I release the button. (Which I do quite quickly.)
There's plenty of amperage to run the tool at sanding load as long as I don't push it really hard, but I need to figure a way to get that big motor spinning. I'd really like to avoid buying a soft start or something like that since it's both expensive and requires a bunch of rewiring. Is there a way to add some big capacitors or something to get past the inrush?
Thanks,
-Ben